Oil sands, also known as “tar sands” and “bituminous sands,” are a mixture of bitumen (tar), sand, and water. Bitumen is a heavy, viscous crude oil, having relatively high sulfur content. When properly separated from the oil sands, bitumen may be processed to synthetic crude oil suitable for use as a feedstock for the production of liquid motor fuels, heating oil, and petrochemicals. Oil sand fields exist throughout most of the world. Particularly significant deposits exist in Canada, including the Athabasca oil sands in Alberta, the United States, including the Utah oil sands, South America, including the Orinoco oil sands in Venezuela, and Africa, including the Nigerian oil sands http://en.wikipedia.org/wiki/Orinoco_Belt. A majority of all of the known oil in the world is contained in oil sands.
Bitumen is very difficult to separate from oil sands in an efficient and environmentally acceptable manner. Current efforts to separate bitumen from oil sands typically yield only about 85-92% of the available bitumen. Moreover, current efforts to separate bitumen from oil sands include the creation of emulsions, or “froth,” during processing, requiring the use of environmentally harmful organic solvents such as naphtha to “crack” the emulsions and allow for further processing. In addition, the bitumen that remains in the sand (and other particulate matter, such as clay) component of the oil sands contributes to the creation of a heavy sludge, often referred to as “tailings.” Current practice for the disposal of the tailings, which are comprised of unrecovered bitumen, sand (and other particulate matter), and water is to pump the tailings into huge tailings ponds, where the sand and other particulate matter slowly settle and stratify over the course of several years.